Manhole structure



1965 I l. w. STEIL 3,220,433

MANHOLE STRUCTURE Filed Aug. 31, 1962 2 Sheets-Sheet 1 INVENTOR /rw'n14/ Jfai/ AfM/way.

Nov. 30, 1965 w. STEIL MANHOLE STRUCTURE 2 Sheets-Sheet 2 Filed Aug. 51,1962 INVENTOR. /rw'n M Jfai/ BY WW4 Affarway.

United States Patent 3,220,433 MANHOLE STRUCTURE Irvin W. Steii, 4622Forest, Kansas City, Mo. Filed Aug. 31, 1962, Ser. No. 220,752 4 Claims.((11. 137363) This invention relates to new and useful improvements inmanhole structures, and has particular reference to manhole structuressuch as are commonly employed at service stations to enclose and concealthe upper end portions of pipes communicating with underground gasolinetanks. Such pipes may constitute means for filling such tanks, in whichcase the pipe is provided with a lockable cap within the manhole, or maycontain gauge mechanism for indicating the quantity of gasoline in thetank, in which case the pipe is provided at its upper end with a caphaving a transparent window through which the gauge may be read. It Willbe understood that the manhole structure provides an underground cavityin which the upper ends of the pipe or pipes are disposed, and which isnormally closed by a manhole cover. The lower end of the cavity must beleft open, to permit rain and other water entering the cavity to drainaway.

In the past, considerable difficulty has arisen in manhole structures ofthis type due to the condensation of moisture therein. This condensationoccurs in both hot and cold weather. In cold weather, the relativelywarm ground vapors rising through the open lower end of the manhole bodycontact parts therein which are relatively cold because of coldatmospheric conditions, especially the lower side of the manhole cover,and moisture is consequently condensed therefrom. The condensate thendrips onto the fill-cap locks or gauge windows, and may freeze thereon.The resulting ice often so fouls the locks of fill-caps to such anextent that the locks must be broken to remove the fill-caps, or theymust be thawed, and neoessitates scraping the ice from gauge windowsbefore the gauges may be read. In hot weather, the relatively hot,

moisture-laden atmospheric air may enter under the manhole cover, whichseldom if ever has an air-tight fit, and contact relatively cool partswithin the manhole, with resulting condensation of moisture. Thismoisture will, even in summer when no freezing can occur, cause rapidcorrosion and deterioration of fill-cap locks and other parts, or causedirt, grit and the like to enter and foul lock mechanisms and the like.

The principal object of the present invention is, therefore, theprovision of a manhole structure which is sweatless and frostless, thatis, in which the portion thereof containing parts which may be adverselyaffected by condensation is preserved dry and free from condensation atall times, in both hot and cold weather.

Other objects are simplicity and economy of construction, efficiency anddependability of operation, and adaptability for use in a wide varietyof manhole applications other than those specifically heretoforeenumerated.

With these objects in view, as well as other objects which will appearin the course of the specification, reference will be had to thedrawing, wherein:

FIG. 1 is a vertical sectional view of a manhole structure embodying thepresent invention, shown in connection with the fill-pipe of anunderground tank,

FIG. 2 is a top plan view of the manhole structure shown in FIG. 1, withthe cover removed, and

FIG. 3 is a sectional view taken on line IIIIII of FIG. 1.

Like reference numerals apply to similar parts through out the severalviews, and the numeral 2 applies generally to the body member of themanhole structure, said body member comprising a cylindrical ring 4disposed with its axis vertical, and a cylindrical sheet metal ex-3,226,433 Patented Nov. 30, 1965 tension 6 telescoped into and welded orotherwise securely afiixed at its upper end in ring 4, and dependingtherefrom. The extension is open at both its upper and lower ends.Obviously ring 4 and extension 6 could be formed integrally. However,the use of a separate extension 6 provides that pre-existing manholestructures, most of which include a member corresponding to ring 4, maybe easily adapted for use in the present invention.

Ring 4 is flanged outwardly adjacent its upper end to provide adownwardly recessed, upwardly facing horizontal shoulder 8 whichsupports a manhole cover 10 for closing the upper end of the bodymember. Said cover may be provided with a finger-gripping member 12whereby said cover may be grasped and lifted.

As shown in FIG. 1, body member 2 is installed in the ground with itsupper end flush with the ground surface, or flush with the surface of aconcentrate apron 14 which may be poured thereabout. The lower edge ofbody extension 6 rests in a pair of arcuate grooves 16 formed in theupper surface of a baffle plate 18 which is rectangular in form andnarrower than the diameter of the extension, so that the bottom of theextension has segmental openings 20 to the surrounding earth or sand ateach side of plate 18 (see FIG. 3). The bottom of the body must not becompletely obstructed, but must be at least partially open, to permitrain water or water used to hose down apron 14, and which may enter bodymember 2, to soak away into the ground. Cover 10 seldom if ever fits sotightly as to prevent such water from entering body member 2 to someextent. Bafiie plate 18 serves to support body member 2 while earth orsand is filled in thereabout, and while concrete apron 14 is beingpoured. Its function as a bafile plate will be described presently.

Baffle plate 18 may be formed of metal, wood or other suitable material,and has a circular hole 22 formed centrally therein which fits nuglyabout, for example, the fill-pipe 24 of an underground gasoline tank,not shown, said pipe extending axially upwardly into body member 2.Fitted into the body member is a condenser plate 26 having a generallyfrustro-conical form coaxially with the body member, with its larger endopening upwardly. Said condenser plate cone is provided at its upper endwith a cylindrical portion 28 which fits snugly in the upper portion ofextension 6 and is welded or otherwise affixed therein. At its lowerend, the condenser plate cone is provided with a depending cylindricalextension 30 which is of larger diameter than pipe 24, so as to define anarrow annular space 32 therebetween. Extension 30 depends into annularsheet metal cup member 34 which surrounds pipe 24 and which may beafiixed either to bafiie plate 18 as shown, or to extension 30 by spacedapart webs. The internal diameter of the cup is such that it engagespipe 24 snugly, but the side walls of the cup are spaced apart from coneextension 30, and the lower end of the extension is spaced above thebottom of the cup, whereby to form an unbroken passage from the interiorto the exterior of cone 26.

Fill-pipe 24 may be provided at its upper end with a fill-cap 36threaded thereon, and secured releasably against removal by a padlock 38the hasp of which passes through a perforated lug 40 aflixed to the cap,and through a perforation 42 formed in one end portion of an agled locklever 44, the opposite end of said lever being pivoted at 46 to a lug 48affixed to the pipe below the cup. The structure shown necessitates thatlug 48 be aflixed to the pipe after body member 2, baflie plate 18 cup34 and cone 26 have been positioned about the pipe.

In use, it will be understood that cup 34 is normally full of water, soas to form an air seal between the interior and exterior of cone 26. Incold weather, the relatively Warm, moisture laden ground vapors risinginto body member 2 through openings 20 at its lower end strike the outersurface of condenser cone 26, which is maintained relatively cold byatmospheric air leaking under cover It), and the moisture therein isthereby condensed to liquid form. This moisture flows downwardly alongthe outer surface of the cone to cup 34, filling said cup if it is notalready full, then overflowing said cup to soak into the ground. Theground vapors are prevented from reaching the inner surface of cover1!), or the threads of cap 36 or the working parts of padlock 38, bothby the disposition of cone 26, and by the seal provided by Water in cup24. Thus no condensate is deposited on these parts, and the object ofthe invention is accomplished. It has been found that if cup 34 isdisposed about inches below the ground surface and the manhole is keptcovered, the water in said cup will be prevented from freezing except inthe most extreme winter weather, by ground warmth. In normal winterweather, any frost forming on cone 26 is confined to about the upperhalf of the outer surface of the cone. However, if the water shouldfreeze in the cup in extreme weather, this is not considered to be adisadvantage. The effectiveness of the cup as an air seal is notaffected by freezing of the water therein, and it is extremely unlikelythat in such weather any external water such as rain or wash water wouldenter the manhole and necessitate draining thereof through the cup. Suchexternal water normally flows downwardly through said cup and drainsinto the ground.

In fact, it has been found that in many installations, cup 34 may bedispensed with entirely while still maintaining reasonable efficiency ofoperation, and the device is therefore believed to be inventive even inthe absence of said cup. Ground vapor rising'from the bottom of the bodymember would then be prevented by baflle plate 18 from rising directlyinto the interior of cone 26 through annular passage 32, being deflectedaway from said passage by said bafile to continue its upward movement toengage the outer surface of the cone. While not as highly efficient aswith the cup, the device has been thoroughly tested and found to bequite serviceable in most conditions without the cup.

In hot weather, moisture-laden atmospheric air leaks under cover 10, andmoisture therein is in most manholes condensed by contact with thefill-cap, its lock 38 and other parts, which are maintained relativelycool by the close proximity of the surrounding earth which is muchcolder than said atmospheric air. In the present structure, however, adead-air space is formed between cone 26 and body r member 6, whichinsulates cap 36 and its related parts from the ground, and preventsloss of heat therefrom by radiation. Therefore, with the exception ofheat lost by con duction from pipe 24 to the ground, which is minimal atthe zone of cap 36, the cap, padlock and related parts are maintainedsubstantially at the same temperature as the surrounding air, andsubstantially no condensation occurs thereon. Cone 26 is relativelycool, and condensation therefore forms on the inner surface thereofrather than on cap 36 or the padlock. This condensate drains downwardlyinto cup 34, and overflows said cup to drain into the ground.

While I have shown and described a specific embodiment of my invention,it will be readily apparent that many minor changes of structure andoperation could be made without departing from the spirit of theinvention as defined by the scope of the appended claims.

What I claim as new and desire to protect by Letters Patent is:

1. In combination with the vertically extending upper portion of anunderground pipe communicating at its lower end with an undergroundtank, a manhole structure comprising:

(a) a hollow cylindrical body member of larger diameter than said pipeadapted to be buried in the ground with its axis disposed vertically andwith its upper end substantially fiush with the ground surface, saidbody member concentrically enclosing the upper end portion of said pipeand being open at its upper and lower ends,

(b) a manhole cover adapted to close the upper end of said body member,and

(c) a sheet metal condenser member of generally frustoconical formdisposed in said body member coaxially therewith, the upper end of saidcondenser member being fitted snugly around its entire periphery in theupper portion of said body member, and the lower end of said condensermember'being of reduced diameter and having a circular apertureadmitting said pipe, said aperture being of such diameter as to providea restricted narrow annular space between said condenser member and saidpipe at said aperture.

2. A manhole structure as recited in claim 1 with the addition of:

(a) a horizontal baffle plate disposed at the lower end of said bodymember in closely spaced apart relation below the lower end of saidcondenser member, said baffle plate having an aperture formed thereinfitting snugly about said pipe, and extending horizontally from saidpipe sufficiently to underlie all portions of said annular space.

3. A manhole structure as recited in claim 1 with the addition of:

(a) an upwardly opening annular cup fixed in the lower portion of saidbody member and into which the lower end of said condenser memberextends, said cup having an internal diameter fitting snugly about saidpipe.

4. A manhole structure as defined in claim 3 wherein all portions ofsaid condenser member slope downwardly to ward the bottom aperturethereof, whereby any condensate formed on either the inner or outersurfaces of said cone will drain into said cup.

References Cited by the Examiner UNITED STATES PATENTS 57,742 9/ 1866Marquis 137-24733 X 1,507,531 9/1924 Vaudell l37-247.33 1,526,637 2/1925Hess 137-247.33 X 1,566,052 12/1925 Dabrowski 137247.33

ISADOR WEIL, Primary Examiner.

MARTIN SCHWADRON, Examiner.

1. IN COMBINATION WITH THE VERTICALLY EXTENDING UPPER PORTION OF ANUNDERGROUND PIPE COMMUNICATING AT ITS LOWER END WITH AN UNDERGROUNDTANK, MANHOLE STRUCTURE COMPRISING: (A) A HOLLOW CYLINDRICAL BODY MEMBEROF LARGER DIAMETER THAN SAID PIPE ADAPTED TO BE BURIED IN THE GROUNDWITH ITS AXIS DISPOSED VERTICALLY AND WITH ITS UPPER END SUBSTANTIALLYFLUSH WITH THE GROUND SURFACE, SAID BODY MEMBER CONCENTRICALLY ENCLOSINGTHE UPPER END PORTION OF SAID PIPE AND BEING OPEN AT ITS UPPER AND LOWERENDS, (B) A MANHOLE COVER ADAPTED TO CLOSE THE UPPER END OF SAID BODYMEMBER, AND (C) A SHEET METAL CONDENSER MEMBER OF GENERALLYFRUSTOCONICAL FORM DISPOSED IN SAID BODY MEMBER COAXIALLY THEREWITH, THEUPPER END OF SAID CONDENSER MEMBER BEING FITTED SNUGLY AROUND ITS ENTIREPERIPHERY IN THE UPPER PORTION OF SAID BODY MEMBER, AND THE LOWER END OFSAID CONDENSER MEMBER BEING OF REDUCED DIAMETER AND HAVING A CIRCULARAPERTURE ADMITTING SAID PIPE, SAID APERTURE BEING OF SUCH DIAMETER AS TOPROVIDE A RESTRICTED NARROW ANNULAR SPACE BETWEEN SAID CONDENSER MEMBERAND SAID PIPE AT SAID APERTURE.